1. Field of the Invention
The present invention relates to a connector structure for use in a voice recorder.
2. Description Related to the Prior Art
Voice recorders are known, which are capable of recording voices input through a microphone (refer to JPA 2014-035436). An example of voice recorder has an IC memory for recording audio data as captured through a microphone and a speaker for enabling reproduction of the audio data. This kind of voice recorder may be called IC recorder or the like. Some types of voice recorders have a microphone integrated therein, and other types are provided with an external microphone that is detachably attachable to the recorder body. The voice recorders of those types with an externally attachable microphone are provided with a connector for attaching the external microphone to the recorder body.
As a type of said connector, push-on type is known, for example, from JPU H06-021170. An example of push-on type connector has a connector body with connector terminals, an anti-removal engaging claw provided on the connector body for retaining an object attached thereto, and a coil spring that can expand and contract in the axial direction of the connector body. The coil spring contracts in the axial direction of the connector body as an object to be attached is pushed into the connector body in the axial direction thereof, thereby generating a force biasing the attached object in the opposite direction to the inserting direction, i.e. in the detaching direction. The object to be attached is provided with an engaging hole or the like that is to be engaged with the engaging claw.
The object to be attached is inserted into the connector body against the biasing force of the coil spring till the engaging claw is engaged in the engaging hole. When the engaging claw comes into engagement with the engaging hole, the object to be attached is completely connected to the connector. Then the attached object is moved in the detaching direction by the repulsion due to the resiliency of the coil spring. Thus, a pre-load of the coil spring is applied to the engaging claw and the engaging hole in the axial direction so as to close a gap therebetween.
The push-on type connection thus enables to complete the engagement through the engaging claw only by pushing the attaching object into the connector, making it easy to connect the attaching object. In addition, the push-on type connection applies the pre-load to the engaging hole and the engaging claw by the biasing force of the coil springs, thereby preventing instability or wobbles that may be caused at the joint due to dimensional errors or the like in the connector or the attached object.
A study has been made to attach a hand microphone as an external microphone to a voice recorder such as described in JPA 2014-035436. The hand microphone typically has a substantially cylindrical grip portion, and a microphone main body is mounted on the head of the grip portion, whereas a connector for connecting the hand microphone to a cable (hereinafter referred to as a mikeside connector) is mounted on the tail end of the grip portion. Employing a push-on connector such as described in JPU H06-021170 as a connector of a voice recorder (hereinafter referred to as a recorder-side connector) will make it easy to connect the hand microphone to the voice recorder.
Furthermore, as described above, the push-on type connection prevents the rattles by means of the biasing force of the coil spring. When the hand microphone is attached to the voice recorder, if there is a gap in the joint, the hand microphone will wobble, generating rattles, such as contact noises or friction noises. The larger is the gap, the vibrations become the bigger, and the contact noises or friction noises become the larger. Because the hand microphone will capture the contact noises or friction noises, it is highly necessary to stably retain the hand microphone on the voice recorder.
Meanwhile, the sizes of mikeside connectors of hand microphones greatly vary depending on the types and the manufacturers. Particularly, there are great variations in axial length between mikeside connectors, including the length of a connector housing for accommodating terminal pins of the mikeside connector. The axial length of each mikeside connector has an influence on the amount of thrust into the recorder-side connector. Since the push-on connection provides the engagement by pushing the mikeside connector in the axial direction thereof into the recorder-side connector while compressing the coil spring, the variation in the amount of thrust will lead to changing the pre-load by the coil spring.
With a mikeside connector of a short axial length, the amount of thrust and hence the amount of compression of the coil spring are small, so the repulsive force of the coil spring is weak. The weak repulsive force results in reducing the pre-load on the mikeside connector, lowering the preventive effect against rattles. In contrast, with a mikeside connector of a longer axial length, the amount of thrust and hence the amount of compression of the coil spring are greater, so the repulsive force is stronger. The stronger repulsive force increases the pre-load and enhances the preventive effect against rattles. However, too strong repulsion of the coil spring causes a problem of making the attaching operation uneasy.